英语分站

一、过去完成时：用法：在过去的时间里，两个动作中，发生在前的哪个动作要用过去完成时。
　　结构：had+过去分词

　　After she had finished her homework, she went shopping.

　　They had sold the car before I asked the price.

　　After/before引导的时间状语从句放在句首要在句子后面加逗号，如果放在主句后则不用加。
       1.变疑问句将助动词移到句首

　　Had she finished her homework?

　　2.变否定句在助动词后面加not

　　She hadn’t finished her homework.

　　3.肯定回答及否定回答

　　Yes, she had. No, she hadn’t.

　　4.特殊疑问句：

　　What had she done?

二、现在完成时
构成：主语+助动词have, has+过去分词

用法：
1） 表示过去发生的和现在有某种联系的动作，常和just, usually, already, since等时间副词连用。
　　I have just had lunch. （饱了，不用再吃了。）
　　He has had a cup of tea.（不渴了，不用再喝。）
　　
2） 询问别人是否做过某事一般用现在完成时：
　　Have you finished your homework?
　　Have you been to Beijing?

3） 表示开始于过去并持续到现在的动作
    I have lived in Beijing for twenty years.
    I have worked for this school for 1 year.
4） 表示一种经历，经验：去过…地方，做过…事情，经历过…事情
　　I have never had a bath.
　　I have never seen a film.
　　
　　Have been to表示去过，have gone to 表示去了
　　I have been to London.（人已经回来）
　　He has gone to London.（人还在那里）

5） 表示一种结果， 一般不和时间副词联用
　　I have lost my pen.
　　I have hurt myself.
　　句型变化：
★变疑问句将助动词移到句首，变否定句在助动词后面加not.
　　Have you lost your pen? I have not lost my pen.

★肯定回答及否定回答
　　Yes, I have. / No, I have not.

★特殊疑问句
　　What have you done?
　　What has he done?

一般过去时与现在完成时的区别：
　　凡是有明确的表示过去的时间状语的句子为过去时。
　　注意：有些动词表示的动作有一个终点，不能再延续，因此不能和表示一段时间状语连用。
　　错：I’ve left Beijing for 3 days.
　　对：I left Beijing 3 days ago. I have been away from being for 3 days